JPH0862886A - Two-component developer for electrostatic image development - Google Patents

Abstract

(57) [Summary] [Constitution] When the triboelectric charge amount of the toner for the initial developer is Q _s and the triboelectric charge amount of the replenishment toner is Q _f , | Q _s |> | Q _f |> 0, a two-component developer for developing an electrostatic image. [Effect] The two-component developer for developing an electrostatic image of the present invention can obtain a stable image density from the initial stage even when continuously used, there is no image stain such as fog, or the toner is scattered in a printer or a copying machine. It provides great industrial benefits such as little pollution and stable maintenance of stable image characteristics against environmental changes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-component developer for developing electrostatic images used in electrophotography, electrostatic recording and the like.

[0002]

2. Description of the Related Art A developer used in an electronic copying machine or the like is once attached to an image carrier such as a photoconductor on which an electrostatic charge image is formed in the developing process, and then is transferred to the photoconductor in the transferring process. After being transferred from the sheet to the transfer sheet, it is fixed on the copy sheet surface in the fixing step. At that time, as a developer for developing the electrostatic charge image formed on the latent image holding surface, a two-component developer consisting of a carrier and a toner and a one-component developer not requiring a carrier (magnetic toner, non-magnetic toner). )It has been known.

Toners contained in the developer include positively chargeable toners and negatively chargeable toners. Conventionally, as those imparting chargeability to positively chargeable toners, nigrosine dyes and quaternary ammonium salts have been used. Further, as a material for imparting chargeability to a negatively chargeable toner, a charge control agent such as a metal-containing dye or a coating agent for imparting a predetermined chargeability to a carrier has been known.

[0004]

In recent years, the number of regular development copying machines equipped with a photoconductive organic photoconductor has been increasing, and positive developing toner, silicone resin, fluorine resin, etc. are used as developers for this copying machine. Two-component developers in combination with coated carriers have been used. However, in a copying machine, a developer is used in which a resin-coated carrier in which a part of the core material is coated with a silicone resin or the like and a positively chargeable toner using, for example, a quaternary ammonium salt compound as a charge control agent are combined. When the image is copied, the initial image quality is good, but there is a problem in that the image density is gradually reduced and the gradation is greatly changed during repeated copying for a long time, which causes a change in image quality.

Therefore, an object of the present invention is to provide a two-component developer for developing an electrostatic charge image, which has an excellent initial image quality and has a high image quality even in repeated copying for a long time and which has excellent durability. Another object of the present invention is to provide a two-component developer that does not depend on the environment such as temperature and humidity and has little change over time.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies on such a problem, and as a result, the charge amount of the toner used for the start developer (initial developer) and the charge amount of the toner used for replenishment are different from each other. The inventors have found that excellent developer performance can be obtained by adjusting the change in the charge amount of the developer to an appropriate level, and have reached the present invention.

That is, the gist of the present invention consists of toner and carrier, and when the triboelectric charge amount of the toner for the initial developer is Qs and the triboelectric charge amount of the replenishment toner is Qf,
| Qs |> | Qf |> 0, which is a two-component developer for developing an electrostatic charge image. Hereinafter, the present invention will be described in detail.

As the resin component that can be used in the present invention, known types suitable for toner can be used. For example,
Polystyrene, polychlorostyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer , Styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer and styrene-acrylic acid Phenyl copolymer, etc.), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer and styrene-phenyl methacrylate copolymer) ), Styrene-α-chloracry Methyl acetate copolymer and styrene-
Acrylonitrile-acrylic acid ester copolymers and other styrene resins (styrene or styrene-substituted homopolymers or copolymers), vinyl chloride resins, rosin-modified maleic acid resins, phenol resins, epoxy resins, polyester resins, polyethylene Resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer resin, xylene resin, polyvinyl butyral resin, and polycarbonate resin, etc. are particularly preferable resins for use in the present invention. Examples thereof include styrene resins, saturated or unsaturated polyester resins and epoxy resins. Further, the above resins are not limited to be used alone, but may be used in combination of two or more kinds.

Furthermore, the cross-linking binder resins described in JP-B-51-23354 and JP-A-50-44836, or JP-B-55-6895 and JP-B-63-32180 are described. The non-crosslinked binder resin which has been used can also be used. Further, the glass transition temperature of the binder resin for toner has a transition start temperature (inflection point) of 50 ° C. or higher when measured by a thermal analysis method (differential thermal analysis device, differential scanning calorimetry device, etc.). preferable. 40 ° C if the glass transition temperature is less than 50 ° C
When the toner is left for a long time at the above high temperature, the toner may be agglomerated or adhered, causing a problem in use.

As the colorant used in the present invention, a suitable known pigment or dye can be used. For example, titanium oxide, zinc white, alumina white, calcium carbonate, navy blue, carbon black, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine dye, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallyl methane dye, Anthraquinone dyes, monoazo and diazo dyes and pigments can be used alone or in combination with a colorant corresponding to the color of the toner.

The content of the colorant may be an amount sufficient to color the toner so that a visible image can be formed by development, and for example, it is 0.5 to 2 with respect to 100 parts by weight of the resin.
It is preferably 0 part by weight. Further, preferably 2 to 1
5 parts by weight. Further, the toner of the developer of the present invention may use a known positively-charged or negatively-charged charge control agent alone or in combination, but when the toner of the developer has a blow-off charge amount of positively-charged property. The present invention effectively works.

Examples of positively chargeable charge control agents include nigrosine dyes, quaternary ammonium salt compounds, triphenylmethane compounds, imidazole compounds and polyamine resins. As a negatively chargeable charge control agent, C
Examples include metal-containing azo dyes such as r, Co, Al, and Fe, salicylic acid metal compounds, alkylsalicylic acid metal compounds, and carlix allene compounds. Examples of the quaternary ammonium salt compound include compounds represented by the following general formulas (I) to (V).

[0013]

Embedded image

(In the formula, each of R ₁ , R ₂ , R ₃ and R ₄ represents an alkyl group which may have a substituent or an aralkyl group which may have a substituent, and Y represents hydrogen or Represents a hydroxyl group, wherein R ₁ , R ₂ , R ₃ or R ₄
When is an alkyl group, the number of carbon atoms is preferably 1 to 18, and the aralkyl group is preferably a benzyl group. )

[0015]

Embedded image

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ have the same meanings as in the above general formula (I).)

[0017]

[Chemical 3]

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ have the same meanings as in the above formula (I).)

[0019]

[Chemical 4]

(Wherein R ₁ , R ₂ , R ₃ and R ₄ have the same meanings as in the above general formula (I), A is an aromatic ring residue which may have a substituent, For example,

[0021]

[Chemical 5]

(In the formula, R ₅ and R ₆ each represent a hydrogen atom, an alkyl group which may have a substituent, a hydroxyl group or an amino group). )

[0023]

[Chemical 6]

(In the formula, R ₁ and R ₂ have the same meanings as in the general formula (I), and A has the same meaning as in the general formula (IV).) As the imidazole compound, Examples thereof include compounds represented by formula (VI) or (VII).

[0025]

[Chemical 7]

(In the formula, R ₁₁ , R ₁₂ and R ₁₃ each have a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or a substituent. Represents an optionally substituted aryl group, R ₁₁ , R ₁₂ or R ₁₃
When is an alkyl group, the number of carbon atoms is 1 to 20, respectively.
Is preferred. )

[0027]

Embedded image

(In the formula, R₁₁, R₁₂And R₁₃Is the above general
Has the same meaning as in formula (VI), R ₁₄, R₁₅And R
₁₆Are each a hydrogen atom or an optionally substituted alkyl group.
A kill group, an aralkyl group which may have a substituent, or
It represents an aryl group which may have a substituent. R₁₄, R
₁₅Or R₁₆When is an alkyl group, it is
Each of 1 to 20 is preferable. ) As the triphenylmethane compound, the following general formula (VI
The compound represented by II) is exemplified.

[0029]

[Chemical 9]

(In the formula, R ₁₇ represents an alkyl group. R ₁₇
1-5 are preferable as the number of carbon atoms. ) Color index number S for Nigrosine dyes
The one represented by the event Black 7 is exemplified, and the surface thereof may be modified. As commercially available products, there are Bontron series manufactured by Orient Chemical Industry (EX, No1, No2, No3, No4,
No7, No9, No10, No11, Bs) and the like.

In particular, when a quaternary ammonium salt compound is used as a charge control agent and is combined with a silicone resin-coated carrier, the initial charge amount of the developer is relatively low, but the charge amount becomes higher as copying is performed. The present invention effectively works because the problem that the image density changes in accordance with the change in the charge amount becomes remarkable. The amount of the charge control agent may be selected according to the desired amount of charge, and the amount of the charge control agent added is preferably about 0.01 to 10 parts by weight with respect to 100 parts by weight of the resin. It may be internally added to the inside, externally added to the surface of the toner particles, or further added to the developer for use.

In addition, a small amount of an auxiliary agent may be added as a toner constituent component of the developer of the present invention for the purpose of improving thermal properties and physical properties, and examples thereof include polyalkylene wax, paraffin wax, higher fatty acid, fatty acid amide, Metal soap etc. can be used. The addition amount is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the toner particles. As the external additive of the toner used in the present invention, various known external additives can be used for the purpose of fluidity improver, resistance adjuster, charge adjuster, abrasive, etc., preferably silicon oxide, aluminum oxide, and oxide. At least one or more selected from titanium, magnetite, ferrite, conductive titania, and hydrotalcite compounds may be used.

An external additive used for the purpose of a fluidity improving agent or a charge control agent is used as a first external additive, and as the external additive, silicon oxide, aluminum oxide, titanium oxide prepared by a wet method or a dry method is used. Fine oxide powder such as, and more preferably, oxide fine powder organoalkoxylane, organochlorsilane, organosilazane, organodisilane,
A hydrophobized material such as a silane coupling agent such as organosilane is preferable. Further, the BET specific surface area (S1) of the first external additive is preferably 20 to 500 m ² / g. Within this range, the storage stability of the toner, the replenishment property from the toner supply section to the developing device, and the developing section are improved. It has excellent toner transportability. If the specific surface area is less than 20 m ² / g, sufficient fluidity improving function and transport function cannot be imparted, and if it is more than 500 m ² / g, the partitioning function between toner particles is reduced, so that toner aggregation and sticking during high temperature storage are prevented. There is a problem in that it is easy to invite and filming to the photoconductor is likely to occur.

An external additive used for the purpose of a resistance adjusting agent, a charge adjusting agent, and an abrasive is used as a second external additive.
Magnetite fine particles, ferrite fine particles, conductive titania doped with tin, antimony and the like, hydrotalcite compounds and the like are preferable, and a known coupling agent, amino group-containing styrene resin and the like may be surface-treated if necessary. Furthermore, the BET specific surface area (S
2) is preferably 1 to 50 m ² / g. Specific surface area is 1m ²
/ Is less than g and the deep groove-like scratches on the photosensitive member occurs, 50 m ²
If it is larger than / g, it is not preferable because the photoreceptor does not have a proper polishing effect. Further, the relationship between the specific surface areas of the first external additive and the second external additive is preferably S1> S2. Outside this range, the effect of adding the external additive does not sufficiently function, which is not preferable.

The amount of these additives to be used may be appropriately selected depending on the desired performance, and is preferably about 0.005 to 10 parts by weight with respect to 100 parts by weight of the resin. Addition amount is 0.
If the amount is less than 005 parts by weight, the intended effect is not exhibited, and if the amount is more than 10 parts by weight, there is a problem that filming occurs on the photoconductor. The relationship between the triboelectric charge amount (Qs) of the toner for the initial developer and the triboelectric charge amount (Qf) of the replenishment toner used in the present invention is | Qs |> | Qf |> 0,
The adjustment of Qs and Qf may be performed by the type and amount of the external additive of the toner. In the case of | Qs | ≦ | Qf |, it is not preferable because the amount of charge on the developer increases in the initial stage of actual image pickup, the degree of decrease in toner density increases, and the image density decreases. In the present invention, the charge amount can be made different by changing the kind and / or the amount of external additive of the toner for initial developer and the toner for replenishment. For example, when the toner is positively charged, as the external additive used in the toner for the initial developer, many external additives that show positively charged properties to the carrier are used, or few external additives are negatively charged to the carrier. The charge may be adjusted by using it. Particularly, in the case of positively chargeable toner, it is preferable to use at least a hydrotalcite compound as an external additive. Known hydrotalcites can be used, and examples thereof include compounds represented by the following general formula (IX) or (X).

[0036]

[ _Equation 1] M ¹ _y1・ M ² _y2・ M ³ _x・ (OH) ₂・ A _{x / n}・ mH ₂ O (IX)

The meanings of the symbols in the above general formula (IX) are as follows. M ¹ : at least one divalent metal selected from the group consisting of Mg, Ca, Sr and Ba M ² : at least one divalent metal selected from the group consisting of Zn, Cd, Pb and Sn M ³ : 3: Valent metal A: n-valent anion n: natural number x, y1, y2, and m are positive numbers that satisfy the following functional expressions.

0 <x ≦ 0.5 y1 + y2 = 1−x 0 ≦ m <2

[0039]

[Equation 2] M ⁴ _(1-x)・ M ⁵ _x・ (OH) ₂・ A _{x / n}・ mH ₂ O …… (X)

The meanings of the symbols in the above general formula (X) are as follows. ^{M 4: Mg, Mn, Fe} , Co, Ni, Cu and Zn 1 or more bivalent metal selected from the group consisting of M ^5: 3-valent metal A: n-valent anion n: natural number x, m the following A positive number that satisfies the function expression.

0 <x ≦ 0.5 0 ≦ m <2 In the above general formula (IX), M ¹ may be at least one divalent metal selected from the group consisting of Mg, Ca, Sr and Ba. , Which can be appropriately selected, and among them, preferable examples include Mg, Ca, Mg and Ca, Mg and Sr, M
Examples thereof include g and Ba. Furthermore, Mg or M
g and Ca can be mentioned as more preferable examples.

M ² in the above general formula (IX) is Zn, C
1 or more 2 selected from the group consisting of d, Pd and Sn
Any valent metal may be used and can be appropriately selected. Among these, preferred examples are Zn, Cd, Pb, Zn and Cd.
Can be exemplified. Furthermore, Zn and / or Cd can be mentioned as a more preferable example. M ³ in the above general formula (IX) is a trivalent metal, such as Al or B.
Examples thereof include i, In, Sb, B and Ti. Among these, Al is more preferable.

In the above general formula (IX), A represents an n-valent anion, for example, CO ₃ ²⁻ , OH ⁻ , HC.
O ₃ ⁻ , salicylate ion ⁻ , citrate ion ^{3 −} , tartrate ion ^{2 −} , NO ₃ ⁻ , I ⁻ , (OOC—COO) ^{2 −} ,
Examples include [Fe (CN) ₆ ] ^4- . Among these, more preferable examples include CO ₃ ^2- and O.
H ^- can be mentioned.

In the above general formula (IX), x is 0 <x≤.
0.5, preferably 0.2 ≦ x ≦ 0.5, more preferably 0.2 ≦ x ≦ 0.4, especially 0.25 ≦ x ≦ 0.3
5 is a positive number, y1 + y2 corresponds to 1-x, and y1 ≧
It is more preferable that y2 is satisfied, and particularly y1> y2 is further preferable. Further, m is a number satisfying 0 ≦ m <2. m =
In order to obtain a compound having a m value of 0 or close to 0, it is preferable to use a compound treated with decrystallized water.

On the other hand, in the above general formula (X), M ⁴ may be any one or more divalent metals selected from the group consisting of Mg, Mn, Fe, Co, Ni, Cu and Zn, and can be appropriately selected. Of these, Mg is particularly preferable. In addition, in the above general formula (X), M ⁵ is a trivalent metal, for example, Al, Fe, Cr, Co, In
And the like, but among these, Al is more preferable.

A in the general formula (X) is an n-valent anion.
For example, CO₃ ^2-, OH^-, HCO₃ ^-, Sari
Citrate ion^-, Citrate ion^3-, Tartrate ion^2-,
NO ₃ ^-, I^-, (OOC-COO)^2-, [Fe (C
N)₆]^Four-And the like. Among these
As a more preferable example, CO₃ ^2-To mention
Wear.

In the above general formula (X), x is 0 <x≤.
A positive number of 0.5, preferably 0.1 ≦ x ≦ 0.4,
Further, m is a number satisfying 0 ≦ m <2. In order to obtain a compound having a small m value of m = 0 or close to m = 0, it is preferable to use a decrystallized water-treated product. The compounds (IX) and (X) according to the present invention each have a crystal particle size of about 0.1 to about 1 μm.
And a BET specific surface area of about 50 m ² / g
The following is preferable, and about 30 m ² / g or less is more preferable.
Further, it is preferable to use those having an average secondary particle diameter of about 5 μm or less, more preferably about 2 μm or less, and especially about 1 μm or less.

In the present invention, for the purpose of improving the releasability of the compound itself, the triboelectric charging property with respect to the developer, the adsorptivity, etc., the compounds represented by the general formulas (IX) and (X) are added to the surface treatment agent. Can be surface treated. Examples of such surface treatment agents include higher fatty acids, anionic surfactants, silane coupling agents, titanate coupling agents, esters of glycerin and fatty acids, and the like. It is not limited to.

As the method for producing toner particles of the developer of the present invention, various conventional toner production methods can be applied. For example, as a general example, first, a resin, a colorant,
Wax, charge control agent, etc. are uniformly dispersed and mixed in a mixer,
Then, the mixture is melt-kneaded by a closed kneader or a single-screw or twin-screw extruder, cooled, coarsely crushed by a crusher, hammer mill, etc., finely crushed by a jet mill, high-speed rotor rotary mill, etc. Classification may be performed with a classifier (for example, an inertia classification type elbow jet, a centrifugal classification type microplex, a DS separator, etc.). The average particle size of the toner is preferably 3 to 20 μm.

When the toner is externally added, the classified toner and the external additive are mixed with a high-speed agitator (Henschel mixer,
Stir and mix with a super mixer, etc.). The carrier of the present invention may be a magnetic carrier such as iron powder, magnetite powder, or ferrite powder as the core material, and may be a resin-coated carrier in which at least a part of the core material is coated with a silicone resin. As the carrier, those having an average particle size larger than that of the toner of about 20 to 200 μm can be used. As a ferrite core material, a general formula (MO) _m (Fe ₂ O
₃ ) A ferrite powder represented by _n is preferable, and the (MO) component is CuO, ZnO, NiO, FeO, Mn.
One or more components such as O, MgO, and BaO may be selected and used.

The silicone resin is composed of macromolecules in which silicon atoms are bonded to each other through siloxane bonds and extend and spread in a network shape. A silicon atom which is bonded only to a silicon atom usually has a hydroxyl group, but a methyl silicone resin or methylphenyl resin which is a resin in which a part of this hydroxyl group is substituted with a methyl group or a methyl group and a phenyl group. Silicone resins are preferred.
If necessary, a silicone resin curing catalyst such as an acid, alkali, amine, or organic acid salt of a metal may be used. Further, styrene-acrylic resin, acrylic resin, epoxy resin, polyester resin, modified silicone resin or the like may be used in combination as a resin to be coated appropriately.

The method for forming the film on the carrier core material may be carried out in the same manner as a known ordinary method. For example, a silicone resin is dissolved or dispersed in an organic solvent to prepare a coating solution, and a dipping method, a dry spray method and The core material is coated by a fluidized spray method using a flow coater, dried, and then heated to cure. The developer is obtained by mixing and stirring the toner and the resin-coated carrier with a known mixing device such as a ball mill, a V-type mixer, a Y-type mixer, a Nauter mixer, a super mixer, etc., and a mixing ratio of the carrier and the toner. Is preferably 5 to 100 parts by weight of carrier with respect to 1 part by weight of toner. <Method for measuring BET specific surface area> The BET specific surface area can be measured by using a commercially available BET specific surface area device by nitrogen adsorption, and for example, a flow-type specific surface area automatic measuring device (Flow Soap 2300 manufactured by Shimadzu Corporation) can be used. Shape) etc. <Method for measuring triboelectric charge amount of toner> 9.6 g of carrier used for developer and 0.4 g of toner are put in a glass bottle, mixed and stirred for 15 minutes with a shaker to prepare a developer, and the charge amount of the developer Is measured by a blow-off measuring device manufactured by Toshiba Chemical. The conditions of the blow-off charge amount measuring device are as follows: blow pressure is 1 kg / cm ² , the wire mesh used is 300 m mesh SUS, measurement time is 20 seconds, charge amount is measurement time 2
Calculated with the maximum value for 0 seconds.

[0053]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the following examples, simply "parts" means "parts by weight". Toner a:

[0054]

[Table 1] Styrene / n-butyl acrylate = 82/18 copolymer resin 100 parts (flow softening temperature 130 ° C, glass transition temperature 61 ° C) Colorant carbon black MA100S 6 parts Low molecular weight polypropylene 550P 2 parts (SANYO) Chemical Industry Co., Ltd.) ・ Charge control agent Bontron P51 2 parts (Orient Chemical Co., Ltd., quaternary ammonium salt compound)

The resulting mixture was kneaded using a continuous twin-screw extruder, cooled, pulverized, and classified to obtain a black toner a having an average particle size of 10 μm. The black toner a was subjected to the external additive treatment of Examples and Comparative Examples to prepare a toner for initial developer and a toner for replenishment. 4 parts of the obtained toner for initial developer and 96 parts of a resin-coated carrier having an average particle size of 100 μm and a saturation magnetization of 55 emu / g, obtained by surface-coating a core material of Cu—Zn-ferrite powder with a resin containing methyl silicone, were V-type mixer. Were mixed and stirred to prepare an initial developer.

Next, an organic photoconductor is used as a photosensitive member by using an initial developer and a replenishment toner, and a magnetic permeability sensor is used to control the toner replenishment to a developer in a developing roll, a heat roll fixing system, a blade cleaning system. Regular development method with a copying speed of 27 sheets (A4) / minute (photoconductor surface potential: DC-500V, bias voltage: DC-200V)
Copier, normal environment temperature 23 ~ 25 ℃, humidity 50 ~
A live-action test of 20,000 sheets was carried out in an environment of 55% RH.

Example 1 Toner for Initial Developer To 100 parts of toner a, silica powder (R972 manufactured by Nippon Aerosil Co., BET specific surface area: 110 m ² / g) was used.
0.2 parts and hydrotalcite compounds (Mg _0.5 · Zn _0.17 · Al _0.33 · (OH) ₂ · treated with fatty acid
(CO ₃ ) _0.165・ 0.45H ₂ O, BET specific surface area:
Toner S1 was obtained by externally adding 0.1 part of 8 m ^{2 /} g) using a Henschel mixer.

Replenishment toner: To 100 parts of toner a, silica powder (R972 manufactured by Nippon Aerosil Co., Ltd., BET specific surface area: 110 m ² / g)
0.25 parts and hydrotalcite compounds (Mg _0.5 · Zn _0.17 · Al _0.33 · (OH) ₂ · treated with fatty acid
(CO ₃ ) _0.165・ 0.45H ₂ O, BET specific surface area:
8m ² /g)0.1 parts of magnetite powder (primary particle size: 0.25 micron, BET specific surface area: 7m ² / g) 0.
Toner F1 is obtained by externally adding 3 parts to a Henschel mixer.
I got

Evaluation results The results are shown in Table 1. The copy image density is stable from the initial stage, there is no increase in the fog which is the stain on the white background of the copy, the toner scattering amount is small, and the inside of the copying machine is not contaminated. It was a good developer and a toner excellent in durability and copy image stability even after continuous copying.

Example 2 Toner for Initial Developer To 100 parts of toner a, silica powder (R972 manufactured by Nippon Aerosil Co., BET specific surface area: 110 m ² / g) was used.
0.2 parts and hydrotalcite compounds (Mg _0.5 · Zn _0.17 · Al _0.33 · (OH) ₂ · treated with fatty acid
(CO ₃ ) _0.165・ 0.45H ₂ O, BET specific surface area:
8m ² /g)0.3 parts of magnetite powder (primary particle size: 0.25 micron, BET specific surface area: 7m ² / g) 0.
Toner S2 after externally processing 3 parts with Henschel mixer
I got

Replenishment toner: Toner F1 of Example 1 was used. -Evaluation results Both image density and fog were good.

Example 3 Toner for Initial Developer To 100 parts of toner a, silica powder (R972 manufactured by Nippon Aerosil Co., BET specific surface area: 110 m ² / g) was used.
0.2 parts and hydrotalcite compounds (Mg _0.75 · Al _0.25 · (OH) ₂ · (CO ₃ ) treated with fatty acid
_0.125・ 0.5H ₂ O, BET specific surface area: 11m ² /
g) 0.05 part was externally added with a Henschel mixer to obtain a toner S3.

Replenishment toner To 100 parts of toner a, silica powder (R972 manufactured by Nippon Aerosil Co., BET specific surface area: 110 m ² / g)
0.25 parts and hydrotalcite compounds (Mg _0.75 · Al _0.25 · (OH) ₂ · (CO ₃ ) treated with fatty acid
_0.125・ 0.5H ₂ O, BET specific surface area: 11m ² /
g) 0.1 part and magnetite powder (primary particle size: 0.
25 μ, BET specific surface area: 7 m ² / g) 0. Two parts were externally added with a Henschel mixer to obtain a toner F3. -Evaluation results Both the copy image density and fog were good.

Comparative Example 1 The toner F1 of Example 1 was used for both the initial developer toner and the replenishment toner. -Evaluation results The image density was greatly reduced at the initial stage, and the initial fog was a little bad.

Comparative Example 2 The toner S3 of Example 3 was used as both the initial developer toner and the replenishment toner. -Evaluation results The image density was greatly reduced at the initial stage. <Brief Description of Measurement Methods, etc.> Image Density: A value obtained by measuring a black portion on which an image is formed with a Macbeth reflection densitometer. Fog: Contamination on the white background where no image is formed is measured using the Nippon Densetsu color difference meter, and the whiteness of the Hunter (Wb) before and after actual copying of the paper used.
Was measured, and the value obtained from the difference between the values before and after was measured as the fog.

[0066]

INDUSTRIAL APPLICABILITY The two-component developer for developing an electrostatic charge image of the present invention can obtain a stable image density from the beginning even when continuously used, there is no image stain such as fog, or toner in a printer or a copying machine. There is little pollution due to scattering, and further, it provides great industrial benefits such as stable maintenance of stable image characteristics against environmental changes.

[0067]

[Table 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G03G 9/10 351 352 (72) Inventor Mikio Uno 370 Enzo, Chigasaki, Kanagawa Mitsubishi Kasei Co., Ltd. Chigasaki Co., Ltd. In the office

Claims (7)

[Claims] 1. When the triboelectric charge amount of the toner for the initial developer is Qs and the triboelectric charge amount of the replenishment toner is Qf, it is | Qs |> | Qf |> 0. A characteristic two-component developer for electrostatic image development. 2. The two-component developer for developing an electrostatic charge image according to claim 1, wherein the carrier is a resin-coated carrier in which at least a part of a core material is coated with a resin. 3. The two-component developer for developing an electrostatic charge image according to claim 2, wherein the resin is a silicone resin. 4. The two-component developer for developing an electrostatic charge image according to claim 1, wherein the toner further contains an external additive. 5. The two-component developer for developing an electrostatic charge image according to claim 4, wherein the type and / or the amount of external additives contained in the toner for initial developer and the toner for replenishment are different from each other. . 6. The external additive is at least one selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide, magnetite, ferrite, conductive titania, and hydrotalcite compounds. Item 2. A two-component developer for developing an electrostatic image according to Item 4 or 5. 7. The two-component developer for developing an electrostatic charge image according to claim 1, wherein the toner is positively charged.